Perspective correct vector graphics with foveated rendering

ABSTRACT

Various implementations disclosed herein include devices, systems, and methods that implement rendering processes that performs vector graphic rendering based on information received from a source application. Various implementations disclosed herein include devices, systems, and methods that implement foveated rendering using content received from a source by selectively drawing the content for only some regions based on gaze.

CROSS-REFERENCE TO RELATED APPLICATIONS

This Application claims the benefit of U.S. Provisional Application Ser.No. 63/190,918 filed May 20, 2021, which is incorporated herein in itsentirety.

TECHNICAL FIELD

The present disclosure generally relates to electronic devices thatrender vector graphics and, in particular, to systems, methods, anddevices that provide foveated rendering for perspective correct vectorgraphics.

BACKGROUND

Existing rendering techniques may use an undesirable amount of anelectronic device's resources (e.g., CPU and/or GPU computations, time,power, etc.). Existing rendering techniques may not accurately orefficiently depict complex vector graphics (e.g., text). Further,existing rendering techniques may not provide perspective correctgraphics for content imported or otherwise provided from existingapplications and/or different environments. For example, 2D content maynot be displayed with accurate perspective when imported into and thusviewed within a rendered 3D environment.

SUMMARY

Various implementations disclosed herein include devices, systems, andmethods the perform a rendering process that performs foveated textrendering using content received from a source (e.g., a mobile deviceapp). For example, the content that would be displayed by an app on thescreen of a mobile device may be displayed using a flat virtual surfaceat a position within a 3D environment. Rather than receiving a bitmapfrom the source (e.g., the mobile device app), the rendering processuses vector drawing commands that define the content from the source torender the content. Moreover, such vector drawing commands may be usedto provide foveated rendering of the content from the source. In someimplementations, the source is an application that provides contentusing API calls to API procedures of a drawing engine. The renderingprocess can be configured to render such content from a source withoutrequiring that the source (e.g., mobile device app) be changed, forexample, by instead changing the drawing engine API procedures. Therendering process can provide foveated rendering by drawing regionsbased on gaze direction (e.g., drawing only some regions, drawing someregions at higher resolution/higher frame rate, etc.). In someimplementations, the rendering process provides an increase in qualityin a focus region, compatibility with applications executing on existingelectronic devices such as smart phones, tablets, or watches, theperception of perspective correct vector graphics and animation, and/orreduces the amount of computation and memory used in providingperspective correct rendering.

In general, one innovative aspect of the subject matter described inthis specification can be embodied in methods that include the actionsof obtaining vector graphic drawing commands corresponding to contentgenerated by a source for display in a first display environment,wherein the source provides the first drawing commands to a drawingengine configured to display the content in the first displayenvironment by generating a raster graphic using the first drawingcommands, wherein the vector graphic drawing commands are obtained fromthe drawing engine based on the first drawing commands. In someimplementations, a gaze direction of a user of an electronic devicehaving a second display environment different than the first displayenvironment is identified. Then, a first region and second region of adisplay space corresponding to a display of the electronic device isidentified. In some implementations, rendering modes are determined forrendering the content in the first region and the second region based onthe gaze direction, and the content is rendered on the display based onthe vector graphic drawing commands and the rendering modes forrendering the content in the first region and second region.

In general, one innovative aspect of the subject matter described inthis specification can be embodied in methods that include the actionsof obtaining vector graphic drawing commands corresponding to contentgenerated by a source for display in a first display environment. Insome implementations, a gaze direction of a user of an electronic deviceis identifies, and a first region and second region of a display spacecorresponding to a display of the electronic device is identified. Then,rendering modes are determined for rendering the content in the firstregion and the second region based on the gaze direction, wherein, basedon the first region having a first rendering mode and the second regionhaving a second rendering mode, the content is only rendered in thefirst region. Then, the content is rendered on the display based on thevector graphic drawing commands and the rendering modes for renderingthe content in the first region and second region.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the present disclosure can be understood by those of ordinaryskill in the art, a more detailed description may be had by reference toaspects of some illustrative implementations, some of which are shown inthe accompanying drawings.

FIG. 1 illustrates left eye and right eye stereoscopic images providedby an electronic device in providing an extended reality (XR)environment in accordance with some implementations.

FIGS. 2A-2F illustrate an XR environment displayed using foveatedrendering in accordance with some implementations.

FIGS. 3-4 illustrate a layer view of virtual content displayed usingfoveated rendering in accordance with some implementations.

FIG. 5 is a flowchart illustrating an exemplary rendering method thatvariously performs vector graphics rendering using content received froma source application in accordance with some implementations.

FIG. 6 is a flowchart illustrating an exemplary method of foveatedrendering using content received from a source application byselectively drawing the content for only some regions based on gaze inaccordance with some implementations.

FIG. 7 illustrates an exemplary electronic device in accordance withsome implementations.

In accordance with common practice, the various features illustrated inthe drawings may not be drawn to scale. Accordingly, the dimensions ofthe various features may be arbitrarily expanded or reduced for clarity.In addition, some of the drawings may not depict all of the componentsof a given system, method or device. Finally, like reference numeralsmay be used to denote like features throughout the specification andfigures.

DESCRIPTION

Numerous details are described in order to provide a thoroughunderstanding of the example implementations shown in the drawings.However, the drawings merely show some example aspects of the presentdisclosure and are therefore not to be considered limiting. Those ofordinary skill in the art will appreciate that other effective aspectsor variants do not include all of the specific details described herein.Moreover, well-known systems, methods, components, devices and circuitshave not been described in exhaustive detail so as not to obscure morepertinent aspects of the example implementations described herein.

FIG. 1 shows left eye and right eye stereoscopic images that when viewedby a user of an electronic device provide 3D virtual content. As shownin FIG. 1 , a left eye image 110L and a right eye image 110R eachinclude a plurality of regions having different display qualities. Forexample, the left eye image 110L and the right eye image 110R can eachinclude a plurality of regions having different resolutions. When thegaze of a user of the electronic device is known, the left eye image110L and the right eye image 110R may use foveated rendering. A firstregion or focus region 112L, 112R includes a focus area where the gazeof the user of the electronic device lands or is fixated, which isrendered at a first quality (e.g., high resolution or detail). A secondregion 114L, 114R is nearby the first region 112 and is rendered at asecond quality (e.g., medium resolution) lower than the first quality. Athird region 116L, 116R is the remaining portion of the rendered imagein the left eye display 110L and the right eye display 110R,respectively, and is rendered at a third quality (e.g., lowerresolution) lower than the second quality. For example, the third region116L, 116R is a background region. The second region 114L, 114R canprovide a smooth transition between the focus region 112L, 112R and thethird region 116L, 116R. In some implementations, the left eye image110L and the right eye image 110R have more than three regions.

In some implementations, the size of the focus area is based on the gazeof the user of the electronic device. In some implementations, the sizeof the focus area is based on an arc/angle covered by the gaze of theuser. For example, the arc covered by the gaze can be 20 degrees, or anarc/angle between 5 degrees and 20 degrees. Thus, the focus area can bebased on the arc covered by the gaze and a visual distance to therendered content. In some implementations, the size of the focus area isbased on an amount of movement of the gaze of the user (e.g., anincrease in movement increases the size). In some implementations, thefocus area includes an arbitrary number of pixels (e.g., 800 by 800) ofa display device rendered in high resolution. In some implementations,the plurality of regions having different rendering qualities areimplemented using a variable rasterization rate (VRR). For example, aVRR map of the rendered image can be used to track or update the VRR.

In some implementations, the focus region 112L, 112R is larger than thefocus area because the gaze of the user includes constant very minormovements. Having the focus region 112 larger that the focus areareduces an amount of re-drawing of the focus region 112 for multipleframes of the display device.

In some implementations, the plurality of regions having differentrespective rendering quality use arbitrary values, resolutions, orscales. Further, the arbitrary different rendering qualities of theplurality of regions can be dynamically changed. For example, the firstregions 112L, 112R, the second regions 114L, 114R, and the third regions116L, 116R can be rendered at 10×, 4×, and 1× quality, respectively. Insome implementations, the second regions 114L, 114R and the thirdregions 116L, 116R are rendered as images or textures.

Some implementations disclosed herein provide foveated rendering ofcontent from a source (e.g., a user interface provided by a mobiledevice application) within another rendering environment (e.g., within aview of an XR environment). For example, the content that would bedisplayed by an app on the screen of a mobile device may be displayed ona flat virtual surface at a position within a 3D environment. FIGS. 2A-Bprovide an example of a user interface from a source (e.g., anapplication on a mobile device) being rendered in another environment.FIGS. 2C-F illustrate how the depiction of the content from the sourcethat is displayed in the other environment can include perspectivecorrect foveated rendering of the content.

FIG. 2A illustrates a user interface of an application. As shown in FIG.2A, a user interface 210 of an application includes various content. Forexample, the content on the user interface 210 can include a headersection 222, text 224, pictures 226, and icons or links to other contentor applications 228.

FIG. 2B illustrates an electronic device 250 within a physicalenvironment 205. The physical environment 205, in this example, is aroom or an office within a house. The electronic device 250 isconfigured to display views (e.g., view 215) of an XR environment thatinclude images of (or are otherwise generated based on images and/orother sensor data of) the physical environment 205. As shown in FIG. 2B,the user interface 210 is displayed in the view 215 of the XRenvironment. In some implementations, the electronic device 250 is anysuitable device for generating and displaying an XR environment such asa smart phone, tablet, or wearable device.

In some implementations, the virtual content (e.g., user interface 210)is displayed relative to a view of the physical environment 205 and thusis displayed based on a defined and potentially fixed position andorientation of a virtual display surface relative to the physicalenvironment. Accordingly, the relative position of the electronic device250 relative to the display surface may depend upon and thus changebased on the location of the electronic device 250 within the physicalenvironment 205. In one position, the view of the electronic device 250may include a close up and head on view of the virtual display surfacewhile in another position, the view of the electronic device may depicta farther away view of the virtual display surface from an angledperspective. Accordingly, the rendering of the virtual content on thevirtual display surface (e.g., how foveated rendering is performed) maydepend upon the relative location of the virtual display surface to theelectronic device 250. The location of the electronic device 250 may bedetermined using various techniques, e.g., computer vision-basedlocalization, simultaneous localization and mapping (SLAM), visualinertial odometry (VIO), etc. and may be based on sensor data, e.g.,image data, depth data, motion data, audio data, etc.

FIG. 2C illustrates foveated rendering of the user interface 210 in a 3Denvironment. Such rendering may occur, for example, when the virtualdisplay surface is positioned at a relatively close up and head onposition relative to the electronic device 250. As shown in FIG. 2C, afocus region 212 is rendered at a first arbitrary foveated scale (e.g.,high resolution), a second region 214 surrounding the focus region 212is rendered at a second arbitrary foveated scale (e.g., mediumresolution), and a background region 216 includes the entire userinterface 210 and is rendered at a third arbitrary foveated scale (e.g.,low resolution). For example, the background region 216 can be a 2Dimage representing the entire user interface 210. Alternatively, thebackground region 216 is not rendered at all.

As the gaze of the user of the electronic device 250 is moved around theuser interface 210, portions of the user interface 210 are re-renderedat the appropriate scale. Thus, as the focus region 212 and the secondregion 214 move around the user interface 210 following the gaze of theuser of the electronic device 250, portions of the user interface 210that newly intersect the moving focus region 212 and the moving secondregion 214 are re-rendered at the appropriate scale. Similarly, portionsof the user interface 210 that no longer intersect the moving focusregion 212 and the moving second region 214 are re-rendered at theappropriate scale of the background region 216.

In some implementations, the vector graphics are rendered with correctperspective in the focus region 212 because the focus region 212intersection with the XR environment can be determined in the 3Dcoordinates of the XR environment. Accordingly, even at extreme anglesbetween the user interface 210 and gaze of the user of the electronicdevice 250, the vector graphics in the focus region 212 are correctlysampled at the right pixel rate in each dimension. In other words, thegaze of the user is projected into the 3D XR environment to determine anintersection (e.g., the focus region 212) with the user interface 210,which is used to dynamically determine an arbitrary scale that providessufficiently high rendering resolution for perspective correct vectorgraphics in the 3D XR environment (e.g., in the focus region 112). Insome implementations, 3D and other special visual effects can be appliedto the foveated rendering of vector graphics in the user interface 210.

As shown in FIG. 2D, the foveated rendered user interface 210 is rotatedabout the x-axis and the y-axis. Such rendering may occur, for example,when the virtual display surface is positioned at a relatively close upand at an angled orientation relative to the electronic device 250. InFIG. 2E, the user interface 210 is rotated horizontally 80 degrees. Suchrendering may occur, for example, when the virtual display surface ispositioned at a relatively close up and at an angled orientationrelative to the electronic device 250. As shown in FIG. 2E, the focusregion 212 (e.g., gaze or the arc covered by the gaze) intersects morethan half of the entire width of the user interface 210. In FIG. 2F, theuser interface 210 is close up and rotated 85 degrees around thevertical axis relative to the electronic device 250. As shown in FIG.2F, the focus region 212 (e.g., gaze or the arc covered by the gaze)intersects vertically more than half of the user interface 210 (e.g.,top to bottom).

FIG. 3 shows an orientation and a front view of an exemplary vectorgraphic displayed in a user interface of an application using foveatedrendering. As shown in FIG. 3, the vector graphic is content 310 (e.g.,a PDF of text) that encompasses a user interface and includes a firstfocus region 312 and a background region 316. Thus, two rendering layersare used for the foveated rendering of the content 310. Again, a gazedirection and therefore a focus area (FA) of a viewer of the content 310is smaller than the focus region 312. In some implementations, the focusregion 312 may be a small section of the content 310. For example, whenreading, most people read a few words at a time in a single row of text,and therefore, the focus region 312 may include four or five words onthat single row of text or include a row above and/or below that singlerow.

In some implementations, the content 310 is divided into a plurality ofgroups of pixels. In some implementations, the content 310 is dividedinto a plurality of pixels called tiles that each have the same shape.In some implementations the content 310 is divided into a plurality oftiles that have the same shape and size.

FIG. 4 shows a layer view of a multiple instances over time of anexemplary vector graphic displayed using foveated rendering. As shown inFIG. 4 , the content 310 (e.g., a PDF of text) is divided into aplurality of tiles (e.g., 42 tiles) drawn in dashed lines that eachinclude a plurality of pixels used to render the content 310. As shownin FIG. 4 , the focus region 312 includes 9 of the tiles and thebackground region 316 includes 33 of the tiles.

FIG. 4 shows that as the gaze of the user moves to the right whilereading the text in the PDF that forms the content 310, the focus region312 including the FA will move to follow the gaze of the user. In oneimplementation, just as (or just before) the focus area or focus region312 crosses into the tiles 20, 27 or 34, those tiles are added to thefocus region 312 (e.g., re-rendered at the scale of the focus region312) and tiles 17, 24, and 31 are dropped from the focus region 312(e.g., re-rendered at the scale of the background regions 316). In FIG.4 , the direction of the movement of the focus region 312 is left toright however, the direction of movement could be right to left, top tobottom, or jump from one section of content to another.

Thus, in some implementations the text or other vector graphics can bedivided into layers (e.g., 2 layers in FIGS. 3-4 ), and only in thefocus region 312 is the text or other vector graphics rendered usingperspective correct vector graphics. The regions (e.g., vector graphics)outside the focus region 312 are not relevant or are rendered usingtechniques that reduce the amount of computation or memory used for therendering.

Various implementations disclosed herein include devices, systems, andmethods the perform a rendering process that performs foveated textrendering using content received from a source (e.g., a mobile deviceapp). For example, the content that would be displayed by an app on thescreen of a mobile device may be displayed using a flat virtual surfaceat a position within a 3D environment. Rather than receiving a bitmapfrom the source (e.g., the mobile device app), the rendering processuses vector drawing commands that define the content from the source torender the content. Moreover, such vector drawing commands may be usedto provide foveated rendering of the content from the source. In someimplementations, the source is an application that provides contentusing API calls to API procedures of a drawing engine. The renderingprocess can be configured to render such content from a source withoutrequiring that the source (e.g., mobile device app) be changed, forexample, by instead changing the drawing engine API procedures.

When receiving the bitmap from these source (e.g., the mobile deviceapp), the rendering process cannot render perspective correct contentbecause the drawing commands are not available to the rendering process.In this example, the bitmap received from the source is a fixedresolution and the rendering process (e.g., using the virtual surface inthe 3D environment) cannot provide perspective correct content, forexample, when zooming-in or zooming-out (e.g., magnification) using thefixed resolution bitmap.

Accordingly, the corresponding vector graphics drawing commands areneeded by the rendering process to render perspective correct complexvector graphics such as text received from a source (e.g., a mobiledevice app) in the 3D environment. In some implementations, therendering process receives the vector graphic drawing commands from thesource (e.g., mobile device app) and renders all vector graphics itselfusing the virtual surface in the 3D environment (e.g., the source doesno rendering). In some implementations, the perspective correct vectorgraphics rendering process modifies the API procedures called by thesource to receive vector graphic drawing commands from the source.Accordingly, since the same API (e.g., call to a library) is calledthere is no change needed to the source (e.g., mobile device app). Thus,in some implementations, the rendering process changes what the sourcesends (via the API call) with the vector graphic rendering requestwithout changing the source itself. Accordingly, the rendering processnow renders all vector graphics to render the content received from thesource and can dynamically change the quality/resolution of the vectorgraphics. Further, the rendering process can scale the vector graphicsfor foveated rendering at the appropriate times. In someimplementations, the rendering process itself can use drawing enginessuch as subdivision techniques (e.g., see FIG. 4 ), CPU-based rendering,raster graphics, etc.

In some implementations, vector graphic rendering techniques describedherein provide foveated rendering with perspective correct vectorgraphic rendering only in a focus region. The perspective correct vectorgraphic rendering is provided using a dynamically changing orientation,size, and/or rendered quality in the focus region. Accordingly, theperspective correct vector graphic rendering is only provided whereneeded (e.g., focus region, 9 tiles in FIG. 4 ). Further, theperspective correct vector graphics rendering process receive all vectorgraphic drawing commands for the XR environment. Thus, the focus regioncan be provided with an arbitrary scale because all vector graphicrendering is done by the rendering process (e.g., compositing server).In addition, the perspective correct vector graphics rendering processis compatible with applications executing on existing electronic devicessuch as smart phones, tablets, watches, or desktops. In someimplementations, vector graphic rendering techniques described hereinprovide foveated rendering with perspective correct vector graphicrendering using layer hierarchies (e.g., a plurality of regionsincluding the focus region), which lowers the amount of computation andmemory used for the rendering.

Vector graphics include paths, which are defined by a start and endpoint, along with other points, curves, and angles along the way. Insome implementations, vector graphics are defined based on vectorgraphics drawing commands that define one or more paths (e.g., lines,curves, or shapes specified by math formulas) and/or that specify thevector graphics' material visual properties (e.g., color, texture,etc.). Vector graphics can be used to define the appearances of variousthings including, but not limited to, text strings, PDFs files, fonts,2D graphics, virtual objects, emojis, etc.

In some implementations, a 2D canvas is a part of a 2D plane, and thecanvas includes all the drawing content for the vector graphic. In someimplementations, the 2D canvas can be warped in 3D (e.g., reflection,distortion, mirroring) to provide 3D effects for the displayed vectorgraphic in a 3D environment.

In one implementation, subdivision techniques (e.g., pre-processing) areused for the foveated rendering of perspective correct vector graphics.The subdivision techniques may be used to reduce number of computationsrequired to render the graphics and/or to reduce the number of curvesused to represent the 2D vector graphic. The subdivision techniques mayenable rendering vector graphics in real time (e.g., every frame) in a3D environment. In some implementations, the subdivision techniques(e.g., pre-processing) are performed in a first processor (e.g., CPU)and the 2D canvas is rendered by a second processor (e.g., GPU) of oneor more electronic devices. In some implementations, the subdivisiontechnique divides the canvas into a plurality of regions of pixels(e.g., see FIG. 4 ). In some implementations, the subdivision techniquedivides the canvas into a plurality of uniformly shaped tiles of pixels.In one example, the tiles are all of the same size. Thus, each tile is aportion of the canvas.

The subdivision technique (e.g., pre-processing) operates to determine alist of relevant drawing commands (e.g., only the drawing commands forpaths that contribute to each tile and then only the portions of thepaths that crossed the tile). In some implementations, the subdivisiontechnique transmits a data structure that is a series of drawingcommands to a processor (e.g., GPU) to render the canvas in a 3Denvironment.

In some implementations, a GPU shader renders the vector graphic byprocessing the transmitted data structure. In some implementations, theGPU shader renders pixels forming the vector graphic by determining (i)what tile contained a pixel, (ii) what drawing commands (e.g., paths)are relevant to this tile, and then determine coverage (e.g., apercentage of the pixel (that has a specific color or materialproperty), color, and composition (e.g., blending partially coveredpixels or visual effects of rendered pixels) for the current pixel.Then, the GPU shader repeats the process for the remaining pixels thatform the vector graphic.

In some implementations, the canvas (e.g., vector graphics) is renderedfor each frame displayed in a 3D environment. However, the subdivisiontechniques are performed only when the content of the canvas is changed.In other words, the subdivision techniques are processed only once foreach non-mutated canvas. For example, for a fixed PDF vector graphic,the subdivision techniques are performed only once for the samedocument, but the PDF vector graphic can be re-rendered in every frameof the 3D environment. In some implementations, only the relevant pixelsin the canvas are rendered with each frame. For example, only the pixelsin the canvas that change are updated. In some implementations, thepixels that change in the canvas are identified by comparing the canvasfor the next frame with the canvas for the current frame.

FIG. 5 is a flowchart illustrating an exemplary method for a renderingprocess that performs vector graphics rendering using content receivedfrom a source (e.g., an application). In some implementations, a 3Denvironment is provided with a view that includes the foveated vectorgraphics and other content (e.g., XR environment or physicalenvironment). For example, the source may be an application thatincludes API calls to a drawing engine (e.g., drawing library). In someimplementations, the display of content from the source can be changedby changing the drawing library API procedures, which removes the needto change the source application itself. For example, rather thanreceiving a bitmap from the source for a text vector graphic (e.g.,“hello world”), the rendering process uses vector graphic drawingcommands from the source to be able to provide foveated vector graphicrendering for the text vector graphic. The foveated rendering processcan draw perspective correct vector graphics in selected regions basedon gaze (e.g., focus region at higher resolution/higher frame rate,etc.) In some implementations, the method 500 is performed by a device(e.g., electronic device 700 of FIG. 7 ). The method 500 can beperformed using an electronic device or by multiple devices incommunication with one another. In some implementations, the method 500is performed by processing logic, including hardware, firmware,software, or a combination thereof. In some implementations, the method500 is performed by a processor executing code stored in anon-transitory computer-readable medium (e.g., a memory). In someimplementations, the method 500 is performed by an electronic devicehaving a processor.

At block 510, the method 500 obtains vector graphic drawing commandscorresponding to content generated by a source for display in a firstdisplay environment, wherein the source provides the first drawingcommands to a drawing engine configured to display the content in thefirst display environment by generating a raster graphic (e.g., bitmap)using the first drawing commands, wherein the vector graphic drawingcommands are obtained from the drawing engine based on the first drawingcommands. For example, the source is an application running on asmartphone that generates a view of content including text for displayin the first display environment that is a display on the smartphone.The source/application provides the first drawing commands (e.g., viaAPI calls) to a drawing engine configured to display the content in thefirst display environment by generating a raster graphic (e.g., bitmap)for the text using the first drawing commands. However, an updateddrawing engine may alternatively obtain the vector graphic drawingcommands for the text based on the first drawing commands. For example,an API call to an updated drawing engine (e.g., API procedures,compositing server) does not change the source/application making theAPI call, but can be configured to use the vector graphic drawingcommands to render the text as a vector graphic instead of a rastergraphic. For example, the updated drawing engine may obtain a displaylist or container of drawing commands from the source based on thecontent (e.g., for the text) to be displayed on in a second displayenvironment.

At block 520, the method 500 identifies a gaze direction of a user of anelectronic device having a second display environment different than thefirst display environment. In some implementations, the gaze directionis determined using active or passive eye tracking (e.g., illumination)of the user of the electronic device. The gaze direction can be comparedto the content generated by the source/application.

At block 530, the method 500 identifies a first region and second regionof a display space corresponding to a display of the electronic device.In some implementations, the first region and the second region arebased on the gaze direction of the user of the electronic device. Forexample, the first region may intersect the gaze direction and thesecond region does not intersect the gaze direction. In someimplementations, the first region is a focus region and the secondregion is a background region. In some implementations, a size of thefirst region is based on an angle of foveation and a distance to thecontent. In one example, the display of the electronic device is dividedinto a plurality of tiles and the first region is a first subset oftiles based on the gaze direction and the second region is the remainingtiles.

At block 540, the method 500 determines rendering modes for renderingthe content in the first region and the second region based on the gazedirection. In one implementation, the rendering mode for the firstregion is a perspective correct vector graphics rendering mode and therendering mode for the second region is a 2D image or texture.Alternatively, the rendering mode for the first region is an 8× visualquality and the rendering mode for the second region is a 1× visualquality. In one example, the content in the first region is rendered ata display frame rate. In one example, the content in the second regionis rendered once or upon change. For example, a tablet or HMD cancompare a view of current content for the application with the firstregion and the second region.

At block 550, the method 500 renders the content on the display based onthe vector graphic drawing commands and the rendering modes forrendering the content in the first region and second region. In someimplementations, blocks 510-550 are repeatedly performed. In someimplementations, the techniques disclosed herein may be implemented on asmart phone, tablet, or a wearable device, such as a head-mounted device(HMD) having an optical see-through or opaque display.

FIG. 6 is a flowchart illustrating an exemplary method of foveatedrendering using content received from a source by selectively renderingthe content for only some regions based on a gaze direction. In someimplementations, content is not drawn outside a focus region of a userof an electronic device. In some implementations, perspective correctvector graphics are re-drawn at a frame rate of a display device in thefocus region. In some implementations, content is re-drawn only in thefocus region. In one example, the source is an application running on anelectronic device. In some implementations, the method 600 is performedby a device (e.g., electronic device 700 of FIG. 7 ). The method 600 canbe performed using an electronic device or by multiple devices incommunication with one another. In some implementations, the method 600is performed by processing logic, including hardware, firmware,software, or a combination thereof. In some implementations, the method600 is performed by a processor executing code stored in anon-transitory computer-readable medium (e.g., a memory). In someimplementations, the method 600 is performed by an electronic devicehaving a processor.

At block 610, the method 600 obtains vector graphic drawing commandscorresponding to content generated by a source for display in a firstdisplay environment. In some implementations, the source is aclient/mobile device application. For example, the source could be anapplication running on a source electronic device (e.g., smartphone ortablet device) that generates a view including text and/or other virtualcontent (e.g., a user interface) for viewing.

At block 620, the method 600 identifies a gaze direction of a user of anelectronic device. In some implementations, the gaze direction of theuser is determined using passive or active eye tracking functionality atthe electronic device. For example, the electronic device can be an HMDthat will display a view of a mobile device app's user interface basedon information generated by the current application providing the mobiledevice app's displayable content.

At block 630, the method 600 identifies a first region and second regionof a display space corresponding to a display of the electronic device.In some implementations, the first region is a focus region of thedisplay and the second region is a background region. In someimplementations, the first region is a first subset of a plurality ofregions (e.g., groups of pixels) and the second region is a seconddifferent subset of the plurality of regions outside (e.g., adjacent orsurrounding) the first subset of pixels. For example, the groups ofpixels can be the same shape and size (each group of pixels is arectangular tile in the display space).

At block 640, the method 600 determines rendering modes (e.g., renderedor not rendered) for rendering the content in the first region and thesecond region based on the gaze direction, wherein, based on the firstregion having a first rendering mode and the second region having asecond rendering mode, the content is only rendered in the first region.In some implementations, the content is not rendered by the secondrendering mode in the second region.

At block 650, the method 600 renders the content on the display based onthe vector graphic drawing commands and the rendering modes forrendering the content in the first region and second region. In someimplementations, the first rendering mode only renders the content in afocus region that is the first region. In some implementations, thefirst rendering mode renders the content at a first resolution in thefirst region and a second rendering mode renders the content at a secondreduced resolution in the second region. In some implementations,rendering in the first region is performed at a first frame rate andrendering in the second region is at a second frame rate less than thefirst frame rate. For example, content in the second region is renderedonce or upon change by the second rendering process.

In some implementations, blocks 610-650 are repeatedly performed. Insome implementations, the techniques disclosed herein may be implementedon a smart phone, tablet, or a wearable device, such as an HMD having anoptical see-through or opaque display.

A physical environment refers to a physical world that people caninteract with and/or sense without the aid of electronic systems. Aphysical environment refers to a physical world that people can senseand/or interact with without aid of electronic devices. The physicalenvironment may include physical features such as a physical surface ora physical object. For example, the physical environment corresponds toa physical park that includes physical trees, physical buildings, andphysical people. People can directly sense and/or interact with thephysical environment such as through sight, touch, hearing, taste, andsmell. In contrast, an extended reality (XR) environment refers to awholly or partially simulated environment that people sense and/orinteract with via an electronic device. For example, the XR environmentmay include augmented reality (AR) content, mixed reality (MR) content,virtual reality (VR) content, and/or the like. With an XR system, asubset of a person's physical motions, or representations thereof, aretracked, and, in response, one or more characteristics of one or morevirtual objects simulated in the XR environment are adjusted in a mannerthat comports with at least one law of physics. As one example, the XRsystem may detect head movement and, in response, adjust graphicalcontent and an acoustic field presented to the person in a mannersimilar to how such views and sounds would change in a physicalenvironment. As another example, the XR system may detect movement ofthe electronic device presenting the XR environment (e.g., a mobilephone, a tablet, a laptop, or the like) and, in response, adjustgraphical content and an acoustic field presented to the person in amanner similar to how such views and sounds would change in a physicalenvironment. In some situations (e.g., for accessibility reasons), theXR system may adjust characteristic(s) of graphical content in the XRenvironment in response to representations of physical motions (e.g.,vocal commands).

There are many different types of electronic systems that enable aperson to sense and/or interact with various XR environments. Examplesinclude head mountable systems, projection-based systems, heads-updisplays (HUDs), vehicle windshields having integrated displaycapability, windows having integrated display capability, displaysformed as lenses designed to be placed on a person's eyes (e.g., similarto contact lenses), headphones/earphones, speaker arrays, input systems(e.g., wearable or handheld controllers with or without hapticfeedback), smartphones, tablets, and desktop/laptop computers. A headmountable system may have one or more speaker(s) and an integratedopaque display. Alternatively, a head mountable system may be configuredto accept an external opaque display (e.g., a smartphone). The headmountable system may incorporate one or more imaging sensors to captureimages or video of the physical environment, and/or one or moremicrophones to capture audio of the physical environment. Rather than anopaque display, a head mountable system may have a transparent ortranslucent display. The transparent or translucent display may have amedium through which light representative of images is directed to aperson's eyes. The display may utilize digital light projection, OLEDs,LEDs, uLEDs, liquid crystal on silicon, laser scanning light source, orany combination of these technologies. The medium may be an opticalwaveguide, a hologram medium, an optical combiner, an optical reflector,or any combination thereof. In some implementations, the transparent ortranslucent display may be configured to become opaque selectively.Projection-based systems may employ retinal projection technology thatprojects graphical images onto a person's retina. Projection systemsalso may be configured to project virtual objects into the physicalenvironment, for example, as a hologram or on a physical surface.

In some implementations, the electronic device presenting the XRenvironment is a single device that may be hand-held (e.g., mobilephone, a tablet, a laptop, etc.) or worn (e.g., a watch, a head-mounteddevice (HMD), etc.). In some implementations, functions of theelectronic device are accomplished via two or more communicating (e.g.,wired or wireless) devices, for example additionally including anoptional base station. Other examples include a laptop, desktop, server,or other such device that includes additional capabilities in terms ofpower, CPU capabilities, GPU capabilities, storage capabilities, memorycapabilities, and the like.

FIG. 7 is a block diagram of an example device 700. While certainspecific features are illustrated, those skilled in the art willappreciate from the present disclosure that various other features havenot been illustrated for the sake of brevity, and so as not to obscuremore pertinent aspects of the implementations disclosed herein. To thatend, as a non-limiting example, in some implementations the electronicdevice 700 includes one or more processing units 702 (e.g.,microprocessors, ASICs, FPGAs, GPUs, CPUs, processing cores, or thelike), one or more input/output (I/O) devices and sensors 706, one ormore communication interfaces 708 (e.g., USB, FIREWIRE, THUNDERBOLT,IEEE 802.3x, IEEE 802.11x, IEEE 802.16x, GSM, CDMA, TDMA, GPS, IR,BLUETOOTH, ZIGBEE, SPI, I2C, or the like type interface), one or moreprogramming (e.g., I/O) interfaces 710, one or more displays 712, one ormore interior or exterior facing sensor systems 714, a memory 720, andone or more communication buses 704 for interconnecting these andvarious other components.

In some implementations, the one or more communication buses 704 includecircuitry that interconnects and controls communications between systemcomponents. In some implementations, the one or more I/O devices andsensors 706 include at least one of an inertial measurement unit (IMU),an accelerometer, a magnetometer, a gyroscope, a thermometer, one ormore physiological sensors (e.g., blood pressure monitor, heart ratemonitor, blood oxygen sensor, blood glucose sensor, etc.), one or moremicrophones, one or more speakers, a haptics engine, one or more depthsensors (e.g., a structured light, a time-of-flight, or the like), orthe like.

In some implementations, the one or more displays 712 are configured topresent content to the user. In some implementations, the one or moredisplays 712 correspond to holographic, digital light processing (DLP),liquid-crystal display (LCD), liquid-crystal on silicon object (LCoS),organic light-emitting field-effect transitory (OLET), organiclight-emitting diode (OLED), surface-conduction electron-emitter display(SED), field-emission display (FED), quantum-dot light-emitting diode(QD-LED), micro-electromechanical system (MEMS), or the like displaytypes. In some implementations, the one or more displays 712 correspondto diffractive, reflective, polarized, holographic, etc. waveguidedisplays. For example, the electronic device 700 may include a singledisplay. In another example, the electronic device 700 includes adisplay for each eye of the user.

In some implementations, the one or more interior or exterior facingsensor systems 714 include an image capture device or array thatcaptures image data or an audio capture device or array (e.g.,microphone) that captures audio data. The one or more image sensorsystems 714 may include one or more RGB cameras (e.g., with acomplimentary metal-oxide-semiconductor (CMOS) image sensor or acharge-coupled device (CCD) image sensor), monochrome cameras, IRcameras, or the like. In various implementations, the one or more imagesensor systems 714 further include an illumination source that emitslight such as a flash. In some implementations, the one or more imagesensor systems 714 further include an on-camera image signal processor(ISP) configured to execute a plurality of processing operations on theimage data.

The memory 720 includes high-speed random-access memory, such as DRAM,SRAM, DDR RAM, or other random-access solid-state memory devices. Insome implementations, the memory 720 includes non-volatile memory, suchas one or more magnetic disk storage devices, optical disk storagedevices, flash memory devices, or other non-volatile solid-state storagedevices. The memory 720 optionally includes one or more storage devicesremotely located from the one or more processing units 702. The memory720 comprises a non-transitory computer readable storage medium.

In some implementations, the memory 720 or the non-transitory computerreadable storage medium of the memory 720 stores an optional operatingsystem 730 and one or more instruction set(s) 740. The operating system730 includes procedures for handling various basic system services andfor performing hardware dependent tasks. In some implementations, theinstruction set(s) 740 include executable software defined by binaryinformation stored in the form of electrical charge. In someimplementations, the instruction set(s) 740 are software that isexecutable by the one or more processing units 702 to carry out one ormore of the techniques described herein.

In some implementations, the instruction set(s) 740 include a vectorgraphics generator 742 that is executable by the processing unit(s) 702to foveated perspective correct vector graphic rendering (e.g., a focusregion) according to one or more of the techniques disclosed herein.

Although the instruction set(s) 740 are shown as residing on a singledevice, it should be understood that in other implementations, anycombination of the elements may be located in separate computingdevices. FIG. 7 is intended more as a functional description of thevarious features which are present in a particular implementation asopposed to a structural schematic of the implementations describedherein. As recognized by those of ordinary skill in the art, items shownseparately could be combined and some items could be separated. Forexample, actual number of instruction sets and the division ofparticular functions and how features are allocated among them will varyfrom one implementation to another and, in some implementations, dependsin part on the particular combination of hardware, software, or firmwarechosen for a particular implementation.

It will be appreciated that the implementations described above arecited by way of example, and that the present invention is not limitedto what has been particularly shown and described hereinabove. Rather,the scope includes both combinations and sub combinations of the variousfeatures described hereinabove, as well as variations and modificationsthereof which would occur to persons skilled in the art upon reading theforegoing description and which are not disclosed in the prior art.

Those of ordinary skill in the art will appreciate that well-knownsystems, methods, components, devices, and circuits have not beendescribed in exhaustive detail so as not to obscure more pertinentaspects of the example implementations described herein. Moreover, othereffective aspects and/or variants do not include all of the specificdetails described herein. Thus, several details are described in orderto provide a thorough understanding of the example aspects as shown inthe drawings. Moreover, the drawings merely show some exampleembodiments of the present disclosure and are therefore not to beconsidered limiting.

While this specification contains many specific implementation details,these should not be construed as limitations on the scope of anyinventions or of what may be claimed, but rather as descriptions offeatures specific to particular embodiments of particular inventions.Certain features that are described in this specification in the contextof separate embodiments can also be implemented in combination in asingle embodiment. Conversely, various features that are described inthe context of a single embodiment can also be implemented in multipleembodiments separately or in any suitable subcombination. Moreover,although features may be described above as acting in certaincombinations and even initially claimed as such, one or more featuresfrom a claimed combination can in some cases be excised from thecombination, and the claimed combination may be directed to asubcombination or variation of a subcombination.

Similarly, while operations are depicted in the drawings in a particularorder, this should not be understood as requiring that such operationsbe performed in the particular order shown or in sequential order, orthat all illustrated operations be performed, to achieve desirableresults. In certain circumstances, multitasking and parallel processingmay be advantageous. Moreover, the separation of various systemcomponents in the embodiments described above should not be understoodas requiring such separation in all embodiments, and it should beunderstood that the described program components and systems cangenerally be integrated together in a single software product orpackaged into multiple software products.

Thus, particular embodiments of the subject matter have been described.Other embodiments are within the scope of the following claims. In somecases, the actions recited in the claims can be performed in a differentorder and still achieve desirable results. In addition, the processesdepicted in the accompanying figures do not necessarily require theparticular order shown, or sequential order, to achieve desirableresults. In certain implementations, multitasking and parallelprocessing may be advantageous.

Embodiments of the subject matter and the operations described in thisspecification can be implemented in digital electronic circuitry, or incomputer software, firmware, or hardware, including the structuresdisclosed in this specification and their structural equivalents, or incombinations of one or more of them. Embodiments of the subject matterdescribed in this specification can be implemented as one or morecomputer programs, i.e., one or more modules of computer programinstructions, encoded on computer storage medium for execution by, or tocontrol the operation of, data processing apparatus. Alternatively, oradditionally, the program instructions can be encoded on an artificiallygenerated propagated signal, e.g., a machine-generated electrical,optical, or electromagnetic signal, that is generated to encodeinformation for transmission to suitable receiver apparatus forexecution by a data processing apparatus. A computer storage medium canbe, or be included in, a computer-readable storage device, acomputer-readable storage substrate, a random or serial access memoryarray or device, or a combination of one or more of them. Moreover,while a computer storage medium is not a propagated signal, a computerstorage medium can be a source or destination of computer programinstructions encoded in an artificially generated propagated signal. Thecomputer storage medium can also be, or be included in, one or moreseparate physical components or media (e.g., multiple CDs, disks, orother storage devices).

The term “data processing apparatus” encompasses all kinds of apparatus,devices, and machines for processing data, including by way of example aprogrammable processor, a computer, a system on a chip, or multipleones, or combinations, of the foregoing. The apparatus can includespecial purpose logic circuitry, e.g., an FPGA (field programmable gatearray) or an ASIC (application specific integrated circuit). Theapparatus can also include, in addition to hardware, code that createsan execution environment for the computer program in question, e.g.,code that constitutes processor firmware, a protocol stack, a databasemanagement system, an operating system, a cross-platform runtimeenvironment, a virtual machine, or a combination of one or more of them.The apparatus and execution environment can realize various differentcomputing model infrastructures, such as web services, distributedcomputing and grid computing infrastructures. Unless specifically statedotherwise, it is appreciated that throughout this specificationdiscussions utilizing the terms such as “processing,” “computing,”“calculating,” “determining,” and “identifying” or the like refer toactions or processes of a computing device, such as one or morecomputers or a similar electronic computing device or devices, thatmanipulate or transform data represented as physical electronic ormagnetic quantities within memories, registers, or other informationstorage devices, transmission devices, or display devices of thecomputing platform.

The system or systems discussed herein are not limited to any particularhardware architecture or configuration. A computing device can includeany suitable arrangement of components that provides a resultconditioned on one or more inputs. Suitable computing devices includemultipurpose microprocessor-based computer systems accessing storedsoftware that programs or configures the computing system from a generalpurpose computing apparatus to a specialized computing apparatusimplementing one or more implementations of the present subject matter.Any suitable programming, scripting, or other type of language orcombinations of languages may be used to implement the teachingscontained herein in software to be used in programming or configuring acomputing device.

Implementations of the methods disclosed herein may be performed in theoperation of such computing devices. The order of the blocks presentedin the examples above can be varied for example, blocks can bere-ordered, combined, and/or broken into sub-blocks. Certain blocks orprocesses can be performed in parallel. The operations described in thisspecification can be implemented as operations performed by a dataprocessing apparatus on data stored on one or more computer-readablestorage devices or received from other sources.

The use of “adapted to” or “configured to” herein is meant as open andinclusive language that does not foreclose devices adapted to orconfigured to perform additional tasks or steps. Additionally, the useof “based on” is meant to be open and inclusive, in that a process,step, calculation, or other action “based on” one or more recitedconditions or values may, in practice, be based on additional conditionsor value beyond those recited. Headings, lists, and numbering includedherein are for ease of explanation only and are not meant to belimiting.

It will also be understood that, although the terms “first,” “second,”etc. may be used herein to describe various elements, these elementsshould not be limited by these terms. These terms are only used todistinguish one element from another. For example, a first node could betermed a second node, and, similarly, a second node could be termed afirst node, which changing the meaning of the description, so long asall occurrences of the “first node” are renamed consistently and alloccurrences of the “second node” are renamed consistently. The firstnode and the second node are both nodes, but they are not the same node.

The terminology used herein is for the purpose of describing particularimplementations only and is not intended to be limiting of the claims.As used in the description of the implementations and the appendedclaims, the singular forms “a,” “an,” and “the” are intended to includethe plural forms as well, unless the context clearly indicatesotherwise. It will also be understood that the term “and/or” as usedherein refers to and encompasses any and all possible combinations ofone or more of the associated listed items. It will be furtherunderstood that the terms “comprises” and/or “comprising,” when used inthis specification, specify the presence of stated features, integers,steps, operations, elements, and/or components, but do not preclude thepresence or addition of one or more other features, integers, steps,operations, elements, components, and/or groups thereof.

As used herein, the term “if” may be construed to mean “when” or “upon”or “in response to determining” or “in accordance with a determination”or “in response to detecting,” that a stated condition precedent istrue, depending on the context. Similarly, the phrase “if it isdetermined [that a stated condition precedent is true]” or “if [a statedcondition precedent is true]” or “when [a stated condition precedent istrue]” may be construed to mean “upon determining” or “in response todetermining” or “in accordance with a determination” or “upon detecting”or “in response to detecting” that the stated condition precedent istrue, depending on the context.

What is claimed is:
 1. A method comprising: at a processor of anelectronic device: obtaining vector graphic drawing commandscorresponding to content generated by a source for display in a firstdisplay environment in which content items are positioned in atwo-dimensional (2D) area corresponding to a display surface, whereinthe source provides the first drawing commands to a drawing engine onthe electronic device configured to generate information to display thecontent in the first display environment by generating a raster graphicusing the first drawing commands, wherein the vector graphic drawingcommands are obtained from the drawing engine based on the first drawingcommands; identifying a gaze direction of a user of the electronicdevice having a second display environment in which the content itemsare positioned in a three-dimensional (3D) coordinate system and viewsof the content items are provided based on a user-determined viewpointwithin that 3D coordinate system, wherein the second display environmentis different than the first display environment; identifying a firstregion and a second region of a display space corresponding to a displayof the electronic device; determining rendering modes for rendering thecontent in the first region and the second region based on the gazedirection; and rendering the content on the display based on the vectorgraphic drawing commands and the rendering modes for rendering thecontent in the first region and the second region.
 2. The method ofclaim 1, wherein the content is XR content including text.
 3. The methodof claim 1, wherein the electronic device is a first electronic device,the source is an application executing on the first electronic device,and the first display environment is a display at the first electronicdevice.
 4. The method of claim 1, wherein the source provides the rastergraphic via API calls to the drawing engine to display the content inthe first display environment, and wherein the raster graphic is abitmap.
 5. The method of claim 1, wherein the vector graphic drawingcommands are generated from a list of drawing commands obtained by thedrawing engine in the second display environment via API calls by thesource.
 6. The method of claim 5, wherein the electronic device is afirst electronic device, and the source is an application executing on asecond electronic device different than the first electronic device. 7.The method of claim 1, wherein the first region is a focus region basedon the gaze direction region and the second region is a backgroundregion.
 8. The method of claim 1, wherein a first rendering mode in thefirst region is a foveated perspective correct rendering mode based onthe vector graphic drawing commands.
 9. The method of claim 1, wherein afirst rendering mode in the first region is a first variable resolutionrendering mode and a second rendering mode in the second region is asecond fixed resolution rendering mode, wherein the second fixedresolution is always less than the first variable resolution.
 10. Themethod of claim 1, wherein rendering in the first region is performed ata frame rate of the display and rendering in the second region is at asecond frame rate less than the frame rate of the display or uponchange.
 11. A system comprising: memory; and one or more processors atan electronic device coupled to the memory, wherein the memory comprisesprogram instructions that, when executed on the one or more processors,cause the system to perform operations comprising: obtaining vectorgraphic drawing commands corresponding to content generated by a sourcefor display in a first display environment in which content items arepositioned in a two-dimensional (2D) area corresponding to a displaysurface, wherein the source provides the first drawing commands to adrawing engine on the electronic device configured to generateinformation to display the content in the first display environment bygenerating a raster graphic using the first drawing commands, whereinthe vector graphic drawing commands are obtained from the drawing enginebased on the first drawing commands; identifying a gaze direction of auser of the electronic device having a second display environment inwhich the content items are positioned in a three-dimensional (3D)coordinate system and views of the content items are provided based on auser-determined viewpoint within that 3D coordinate system, wherein thesecond display environment is different than the first displayenvironment; identifying a first region and a second region of a displayspace corresponding to a display of the electronic device; determiningrendering modes for rendering the content in the first region and thesecond region based on the gaze direction; and rendering the content onthe display based on the vector graphic drawing commands and therendering modes for rendering the content in the first region and thesecond region.
 12. The system of claim 11, wherein the content is XRcontent including text.
 13. The system of claim 11, wherein theelectronic device is a first electronic device, the source is anapplication executing on the first electronic device, and the firstdisplay environment is a display at the first electronic device.
 14. Thesystem of claim 11, wherein the source provides the raster graphic viaAPI calls to the drawing engine to display the content in the firstdisplay environment, and wherein the raster graphic is a bitmap.
 15. Thesystem of claim 11, wherein the vector graphic drawing commands aregenerated from a list of drawing commands obtained by the drawing enginein the second display environment via API calls by the source.
 16. Thesystem of claim 15, wherein the electronic device is a first electronicdevice, and the source is an application executing on a secondelectronic device different than the first electronic device.
 17. Thesystem of claim 11, wherein the first region is a focus region based onthe gaze direction region and the second region is a background region.18. The system of claim 11, wherein a first rendering mode in the firstregion is a foveated perspective correct rendering mode based on thevector graphic drawing commands.
 19. The system of claim 11, wherein afirst rendering mode in the first region is a first variable resolutionrendering mode and a second rendering mode in the second region is asecond fixed resolution rendering mode, wherein the second fixedresolution is always less than the first variable resolution.
 20. Anon-transitory computer-readable storage medium, storing programinstructions executable via one or more processors of an electronicdevice to perform operations comprising: obtaining vector graphicdrawing commands corresponding to content generated by a source fordisplay in a first display environment in which content items arepositioned in a two-dimensional (2D) area corresponding to a displaysurface, wherein the source provides the first drawing commands to adrawing engine on the electronic device configured to generateinformation to display the content in the first display environment bygenerating a raster graphic using the first drawing commands, whereinthe vector graphic drawing commands are obtained from the drawing enginebased on the first drawing commands; identifying a gaze direction of auser of the electronic device having a second display environment inwhich the content items are positioned in a three-dimensional (3D)coordinate system and views of the content items are provided based on auser-determined viewpoint within that 3D coordinate system, wherein thesecond display environment is different than the first displayenvironment; identifying a first region and a second region of a displayspace corresponding to a display of the electronic device; determiningrendering modes for rendering the content in the first region and thesecond region based on the gaze direction; and rendering the content onthe display based on the vector graphic drawing commands and therendering modes for rendering the content in the first region and thesecond region.